Frogwatch and the chorus of spring

One of the sure signs of spring here in the Pontiac countryside is the chorus
of frogs. Starting at twilight, or after a sprinkling of rain, their mating
calls fill the air and banish the memory of winter.

Can you imagine a spring without such joyous song?

Hardly. Just like the honking of migrating geese, the burst of white plum and
cherry blossoms, and the rush of returning songbirds, the amphibian chorus
represents an integral part of our Pontiac spring.

But something is amiss in the amphibian world.

Species such as the once-common leopard frog are declining in numbers.

Why? Perhaps it is pesticide use. Perhaps it is habitat destruction. Perhaps
it is global warming, which, in frog terms, is translated into ultra-violet ray
sensitivity and (again) the drying of wetland habitats due to climate, not
direct human intervention.

Because species are in decline, the Canadian Frogwatch Program was initiated.

I found out about it because I am a member of the Canadian Nature Federation.
In the last issue of the association’s magazine, Nature Canada, I received a
large, coloured Frogwatch poster. I decided to investigate the program, using
the Internet. Here’s what I’ve discovered both on the poster and website.

The program

Frogwatch is a national volunteer monitoring program that helps assess what
ecological changes are occurring throughout Canada and their impact on frog
populations. Scientific monitoring methods established by scientists at
Environment Canada’s Ecological Monitoring and Assessment Network (EMAN) are
used for the Frogwatch project.

Frogs and the environment

Frogs are particularly sensitivity to habitat change. Here are some reasons
why. (This list is taken from the Frogwatch poster.)

1. Life history. Frogs live on land and in water and are, therefore,
particularly susceptible to changes in both habitats. From their jelly-like egg
masses through to gill-breathing tadpole and finally the air-breathing adult
frog, each metamorphosis, or change, is complex and exposes the creature to a
variety of potentially harmful stimulae.

2. Permeable skin. Frogs keep their skin moist by absorbing water through
their skin. Therefore, they are particularly susceptible to pollutants like
herbicides and pesticides found in country ponds, streams and ditches.

3. UV-sensitivity. The ozone layer surrounding Earth is shrinking. This layer
protects us from ultraviolet radiation and, because frogs’ eggs are in a
jelly-like mass suspended in water, they are particularly prone to increased
radiation.

Declining frog populations

Herpetologists are scientists who study amphibians and reptiles. In the
1980s, they realized that amphibian populations were declining throughout the
world.

This reduction was evident in both remote wilderness and populated regions.
Therefore, it’s not just direct human intervention (such as draining wetlands
for agricultural land) that is the problem.

Although some foreign species are now extinct (such as Costa Rica’s Golden
Toad and three miniature frogs from Puerto Rico) Canadian frogs are “merely”
suffering a marked decline.

So far.

For example, of the 11 frogs in Québec, the northern leopard frog is already
known to be in trouble. In fact, this species, which was one of the most common
in Western Canada, now is classified as endangered in British Columbia and
Alberta. As early as the 1970s, herpetologists discovered that northern leopard
frogs had vanished from many of their usual habitats.

Something is causing frogs and other amphibians and reptiles to die. What is
it? That’s why Frogwatch is an important project. Scientists need our help in
monitoring frog populations throughout Canada.

Monitoring frogs

Frogs are relatively easy to identify during spring because there are not too
many species at any given site. How can you tell which species are on-site? By
the male’s spring mating calls. And, by visual observation.

If you want to learn how to identify the calls, use your telephone! Simply
telephone 1-888-31FROGS and step your way through the numbering system. First of
all you identify your province, then you get to listen to the calls of Québec’s
11 different species, like the bullfrog, green, mink, northern leopard,
pickerel, wood frog and spring peeper.

Your commitment

Frogwatch participants should commit to monitoring a particular site for a
period of years. The site could be your backyard, your farm pond, the lake at
your cottage. This can be a project that your family, class, Scout or Guide
troop decide to take on. You need to be able to identify the types of frogs by
their sound and by their appearance. Which frogs are calling at a given site?
When do they call (under what conditions, what time of day)? Are they still
calling next year? (This is a particularly important question to answer and
demands a long-term commitment).

Learning about frogs

Are you on the Internet? If you are, find out more about Frogwatch by
clicking on the Canadian Nature Federation website and stepping through the
pages you will find at www.cnf.ca